Lead-in insulator



Patented Apr. 6, 1943 LEAD-IN INSULATOR Paul E. Anderson and Jon Joseph Yolles (also known as Jack Yolles or Jacob Yolles), Dayton,

Ohio

Application March 10,1941, Serial No. 382,538

4 Claims. (01. 174-153) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used for or by the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to insulators and more particularly to radio antenna lead-in insulators for aircraft; and has as its objects the provision of convenient means whereby a conductor of a concentric line transmission system may be efficiently led from the inside to the outside of the airship, the provisions of means for conveniently anchoring the sheath of a concentric transmission line to the body of the aircraft, the provision of means for hermetically sealing the inner parts of the insulator from moisture and gases'and the provision of a very rugged leadin insulator. Other objects and advantages will appear from a study of the attached drawing.

In carrying out the foregoing objects, we provide a cylindrical metal tube with a flange at one end. This flange is located between two discs of insulating material and supported solely by these discs. These discs are held in place by pressure from the end plates of the housing. The sheath of the concentric line fits in one end of our device. A slip-on connection is used to electrically connect the antenna wire to the other electrical end of our device.

In the drawing, Figure 1 illustrates the various parts of our insulator before assembly. Figure 2 is a plan view of the cylindrical member that has the flange. Figure 3 is a sectional view of the slip-on connector to which the antenna wire is fastened. Figure 4 is an end view of the part shown in Figure 3. Figure 5 shows our insulator in assembled form. Figure 6 is a sectional view taken along line 6-6 of Figure 5. Figure 'I is an end view of the insulator of Figure 5.

Our invention comprises a housing 22 into which the Micalex or other low loss insulator 25 is inserted. A lead washer I0 is placed between the insulator 25 and the housing 22. A wire 4| connects to the cylindrical member 23 at point 43 and extends through the hole in that member and away from the left hand end of the device. Another wire 42 connect to slip-on connector 24 at point 64. This wire extends away from the right hand end of the device and to the antenna outside of the airship.

The disc-like Micalex insulators 25 and 26 are respectively separated from the flange 40 by lead washers 28 and 29. Another leadwasher B9 is located between the right end of tubular member 2| and the disc 26.

A guide insulator 33 is cated inside the tubular member 2| to maintain the wire 4| in the center of the tube 2|. The outer housing 22 has thereon nuts 21 and washers 3| to clamp the device to the wall of the aircraft. The threads for nuts 21 run the full length of the housing 22. The concentric cable passes to the left-end of the insulator from the radio set. The outside surface of the sheath of the cable fits snugly in the hole in the tubular member 2| and passes between the insulator 33 and the inner wall of part 2|.

During assembly, the parts are placed together as shown in Figures 1 and 5 except that parts 24, 21, and 3| are not assembled at first. The member 2| is then forced under great pressure toward the right hand end of the housing and compresses the lead washers. The end 44 of the housing 22 is then spun over to hold the various parts tightly together laterally. The close fit of the parts as well as the great pressure between them makes the inside of the device gas-tight.

The device is then inserted in a hole in the wall of the airship and clamped to such a wall with nuts 21 and washers 3|. The part 24 is then put on and fastened by set screw 32.

We have found that use of a slip;on connector such as 24 minimizes breakage of the wire 42. In insulators of the prior art, vibration of the aircraftw often caused breakage of this wire. Slipon connector 24 is streamlined to reduce forces set up thereon due to air pressure. This feature reduces the strain on the internal parts and thereby reduces the likelihood of breakage.

As a result of our mechanical construction, the insulator is subject to less breakage than the devices previously used for aircraft lead-in insulators. The resultant strain on Micalex discs 25 and 26 is quite low and moreover the pressure on these discs insures that the air spaces within our device are airtight and moisture-proof. The sheath of the concentric feed. cable is efiiciently grounded to the body of the airship at 2|.

We claim to have invented:

1. A lead-in insulatorcomprising a cup-shaped metallic housing having an axially located hole in the base thereof; means associated with the outer side wall of the housing for retaining such housing to a wall when the housing is passed axially through at hole in the wall; metallic means including an elongated rod having a flange near one end thereof, said flange being located inside said housing in a plane parallel to the base of said housing and having considerably smaller dimensions in said plane than does the housing, the elongated portion of said rod extending through the hole in the base of the housing for an appreciable distance beyond the outer surface of the base of said housing; two plate insulators, the first of which has an axial hole therethrough and through which said rod passes; said plate insulators being positioned in planes parallel to said flange, respectively on opposite sides of said flange, and both adjacent thereto; the first of said plate insulators being disposed between the flange and the base of said housing and both of said plate insulators being arranged to press firmly on said flange and to hold said metallic means securely in a place away from contact with said housing; a hollow metallic member having outer dimensions whereby the member fits in the relatively open end of said housing and inner dimensions adapted to receive the metallic sheath of a cable, said metallic member being positioned inside said housing and having one end adjacent the particular face of the second plate that is away from the flange; means cooperating with the said side wall of said housing and with said metallic member to force said member toward said base whereby to firmly press a said plates and flange toward each other and thereby hold the flange in place; conducting means attached to said metallic means and passing through the opening in said hollow metallic member and electrically separated therefrom; and conducting means electrically connecting to that portion of said rod that extends beyond the outer surface of said base.

2. In a lead-in device; a cup-shaped metallic housing having a hole in the base thereof; metallic means comprising, a rod extending through said hole so as to have portions both inside and outside of said housing, and a flange rigidly fastened to said inside portion; two insulating plates respectively located adjacent and in contact with opposite faces of said flange, each of said plates including insulating material for insulating the flange from the housing; means pressing said plates toward each other to thereby support the flange and to hold the metallic means within and separated from the housing; a wire of a sheathed cable electrically connected to the rod and extending out of the open end of the housing; and means surrounding said wire, located at and adapted to receive at the open end of said housing the sheath of the cable and electrically connect such a sheath to the housing.

3. In a lead-in device; a cup-shaped metallic housing having a hole in the'base thereof; a

metallic rod of smaller cross-section than said hole and extending through the hole whereby to have portions both inside and outside said housing; supporting means acting as the sole support for the rod and comprising the following parts all in said housing and in planes parallel to said base, a first insulating plate adjacent said base, a flange rigidly attached to said rod and having one of its faces adjacent and in contact with said first plate, a second insulating plate adjacent and in contact with the other face of the flange, said plates having cross-sectional dimensions that snugly fit in the cupshaped housing, and the flange and rod having such small dimensions as to be separated electrically from the housing; and means cooperating with the side wall of the housing for exerting pressure against the second plate, to force the plates toward said base, and maintain the space between the flange and housing sealed from external impurities.

4. In a lead-in insulator, a cup-shaped housing having a hole in the base thereof; a metallic rod of smaller cross-section than said hole and extending through the hole whereby to have portions both inside of and outside of said housing; a metallic flange of smaller cross-section than said housing rigidly attached to said rod; said flange being located inside said housing and in a plane parallel to said base whereby a space exists between the flange and housing; a pair of insulating plates respectively located in planes parallel to said base and on opposite sides of said flange, both of which plates are adjacent the flange and one of which plates is adjacent to said base; means, including a plug having an outer wall which makes an air-tight flt with the inner wall of the cup-shaped housing and located near the open end of the housing, for maintaining a large force on the insulating plate which is on the side of said flange opposite the base to thereby press said insulating plates tightly toward the flange and press the insulating plate which is adjacent said base toward the base;

and means cooperating with said base and said insulating plates to effectuate air-tight seals surrounding said space; and a wire electrically connected to said rod and extending out the open end of said housing.

PAUL E. ANDERSON. JON JOSEPH YOLLES, (Also known as Jack Yolles or Jacob Yolles.) 

